Light-sensitive material



July 27, 10937.

A. VON BlEHl- ER LIGHT SENSITIVE MATERIAL V Filed 001;. 17, 1950 FJ'G. 1,

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@brow v Patented ,July 2Y7, 1937'l I.

' PATE-Nr OFFICE LIGHT- SENSITIVE MATERIAL Arpad von Bichler, Dessau in Anhalt, Germany,

assignor to Agfa Ansco Corporation, Binghamton, N. Y., a corporation of New York Application October 17, 1930, Serial No.` 489,410 In Germany October 23, 1929 4 Claims.

My present invention relates to a new photographic material and more particularly to photographic lms having a stratiecl` base which can be easily divided into some partial layers. One of its objects is to provide a; iilm coated on both sides with a photographic emulsion, wherein the l-m base can be split into two partial layer supports.

Another object of my invention is such a stratiled film which can be separated into two partial layer supports and into a light filter.

Further objects of my invention; will be seen from the detailed specification following hereafter.

It is known to make multi-color photographs by superposing in any order of succession several emulsion layers, sensitized for diierent spectral regions, and exposing them simultaneously behind an objective, if necessary with interposition of suitable filters. By this method, several colcred partial negatives are obtained which are separated after exposure or development and are used forthe preparationof a color positive. As

' in this process it is of great importance that the from the support and fixed on a new support.

This requires, however, very intricate work and the thin emulsion pellicle is liable to be damaged According to my invention, this drawback is avoided by applying the sensitive layers one on each side of a support composed of one or more layers. Although the several strata of the layer support adhere rmly to one another they may easily be separated, for example, by repeatedly sharply bendingthe support at one corner, into two supports each carrying a light-sensitive layer.

Of course, this detachable light-sensitive material may not only .be used for the multi-color 'photography but for all purposes requiring. a material coated on both its sides with emulsion layers which are to be treated separately later on.

The support composed'of several strata,'. may consist of cellulose derivatives as well as of other l, suitable substances, such as artificial resins, rubber, and the like. The support may be composed either of several strata of the same material or of distinct materials of -the same group, for instanceof several strata of diierent cellulose derivatives\` Alternatively I may use for my composite support strata of compounds belonging to different groups, for instance, two cellulose derivative strata and one rubber stratum. When superposing the diiierent layers by casting, care mustbe taken that the vstrata can easily be disconnected. 'I'his can be attained by allowing the first stratum to dry completely before superposing the next stratum and by choosing the solvents of the casting solution tobe applied in such ra manner that they do not dis/solve or vswell the bottom stratum to a noticeable extent.

Besides, the diiierentstrata of the film base may contain any additions known in the manufacture of supports for photographic layers, for

instance, pigments and dyestuiis. If it-is necessary to optically separate the sensitive layers applied on each face of the support, one or several of the strata of the support may be suitably colored to constitute a color lter. If, when printing", this color lter should be inconvenient, the base of the negative lm'may be built up in such a. way that readily detachable strata are tted, in the manner described, at both sides of the stratum containing the filter color, so that the support may be separated into three parts,

namely a filter layer and two' supports "each carrying an emulsion layer.

In the following examples I illustrate in which manner the base of myv new photographic' lms may be made.

Example 1.-Fro'1n -nitrocellulose dissolved in a mixture of 3 parts by volume of acetone and 2 parts by volume of methanol, a film iscast in the known manner. Then, onto this film, a layer of cellulose acetate is applied from an acetone solution. When the latter is completely dried finally, a second nitrocellulose lm is cast there-- on from a solution containing as a solvent a mixture of 3 parts by volume of ether and 1 part by volume of alcohol. The liln base thus obtained,

shows two nitrocellulose' strata enclosing a cellulose acetate stratum which strata firmly adhere.

However, the film base can be split.Y

a rubber layer .cast from a rubber solution in 55 benzene and of a second nitrocellulose stratum, likewise, cast from a solution containing ether and alcohol in the ratio 3:1 and applied to the dried rubber layer.

My invention is not limited by the foregoing examples or by the specific details given therein. Thus, I may use, for instance, other cellulose derivatives or other solvents to prepare the casting solutions, care being taken, however, that the said solvents do not act upon the stratum upon which they are cast. A few simple experiments should be made to determine the best kind of solvent or mixture 'of solvents to employ with a particular compound intended to form a stratum of the composed lm.

f My new film bases may be coated either on one side or on both sides with a light-sensitive photographic emulsion in the known manner.

My invention is further illustrated by the auccompanying drawing in which Fig. 1 shows a lm composed of two strata and Fig. 2 a similar film comprising three strata.

In Fig. 1, A and B are two films consisting, for instance, of the same or different cellulose derivatives or of other materials well known in the art as a lm base. C and C are the light-sensitive emulsions. The strata A and B adhering together, may be separated by detaching. Fig. 2 shows a similar film base comprising three detachable strata of which the middle D may be colored in order to provide a light filter.

The termy different cellulose,derivatives as used in the specification and the claims is intended to cover cellulose derivatives having differing solubility.

v1. -A photographic material comprising a stratifled support, the strata of which consist of at least two dry layers of differently soluble cellulose esters, said layers Vbeing fastened to each other over the whole surface solely by the adherence of the materials of the contacting layers, whereby reduced adhesion of the layers is provided so that they are detachable by mechanical means.

2. A photographic material comprising a stratified support, the strata of which consist of at least two dry layers of differently soluble cellulose esters, said layers being fastened to each other over the whole surface solely by the adherence of the materials of the contacting layers, whereby reduced adhesion of the layers is provided so that they are detachable by mechanical means, and said stratified support being coated on at least one face with a light sensitive emulsion.

3. A photographic material comprising a stratied support the strata of which consist of a nitrocellulose layer and a cellulose acetate layer firmly adhering to each other to form one element and a nitrocellulose layer fastened to said cellulose acetate layer over the whole surface solely by the adherence ofthe materials of the contacting layers, whereby reduced adhesion of the layers is provided, so that they are detachable by mechanlcal means. v

4. A photographic material comprising a stratified support the strata of which consist of a nitrocellulose layer and a cellulose acetate layer fastened to said nitrocellulose layer over the whole surface solely by the adherence of the materials of the contacting layers, whereby reduced adhesion of the layers is provided so that they are detachable by mechanical means.

ARPAD v\. BIEHLER. 

